Electronic musical keyer with touch responsive volume control employing a mechanical electrical transducer

ABSTRACT

A keyboard device for an electronic musical instrument comprising a plurality of keys, a lever located under each of the keys, the lever being swingably supported at one end by a pivot shaft and provided with a weight at the other free end, a mechanical-electrical transducer including a movable magnetic sensor attached to the free end of the lever and a fixed magnet disposed in such position that the magnet applies varied effects on the sensor depending on the relative positions thereof, a drive member fixed on the key to transmit the depression of the key to the lever, and a bridle rod fixed to the key to return the lever when the key is released, the lever being provided in relation to the pivot shaft with sufficient friction force to hold the lever in a depressed position in accordance with the key depressing strength.

United States Patent [72] Inventor HiroshiArnano I-lamamatsu-shi, Japan {21] Appl. No. 848,544

[22] Filed Aug. 8, 1969 [45] Patented May 25, 1971 [73] Assignee Nippon Gakki Seizo Kabushiki Kaisha,

Nakazawwcho v Hamamatsu-shi, Shizuoka-ken, Japan [32] Priority Aug. 13, 1968 [33] Japan [54] ELECTRONIC MUSICAL KEYER WITH TOUCH RESPONSIVE VOLUME CONTROL EMPLOYING A MECHANICAL ELECTRICAL TRANSDUCER 4 Claims, 12 Drawing Figs.

52 us. Cl 84/l.l,

84/Digest 7, 84/I.l5

[5 I] Int. Cl. Gl0h 3/00,

GlOc 3/12, 61% 3/12 [50] Field of Search 84/1 14,

1.15, 1.27, 1.1, 1.01, 1.09, 1.27 D, 1.27 E,1.27 O, 423, 427, 430 [56] References Cited UNITED STATES PATENTS 2,321,366 6/1943 Demuth 84/1.15

Primary Examiner-Milton O. Hirshfield Assistant Examiner-Stanley J. Witkowski Attorney-Stevens, Davis, Miller and Mosher ABSTRACT: A keyboard device for an electronic musical instrument comprising a plurality of keys, a lever located under each of the keys, the lever being swingably supported at one end by a pivot shaft and provided with a weight at the other free end, a mechanical-electrical transducer including a movable magnetic sensor attached to the free end of the lever and a fixed magnet disposed in such position that the magnet applies varied efiects on the sensor depending on the relative positions thereof, a drive member fixed on the key to transmit the depression of the key to the lever, and a bridle rod fixed to the key to return the lever when the key is released, the lever being provided in relation to the pivot shaft with sufficient friction force to hold the lever in a depressed position in accordance with the key depressing strength.

Patented May 25, 1971 3,580,979

3 Sheets-Sheet 1 I INVliN'lQR. HIROSHI AMANO ATTORNEYS Patented May 25, 1971 3,580,979

3 Sheets-Sheet 2 FIG. 4

I NVEN'I -()R. HIROSHI AMANO Mr-MM ATTORNEYS Patented May 25, 1971 3,580,979

3 Sheets-Sheet 3 lNVIiNI'OR.

@ HIROSH. AMANO ATTORNEYS ELECTRONIC MUSICAL KEYER WITII TOUCH RESPONSIVE VOLUME CONTROL EMPLOYING A MECHANICAL ELECTRICAL TRANSDUCER BACKGROUND OF THE INVENTION being constant, electronic musical instruments employ volume 1 controllers, such as an expression controller, which is manually operated separately of the keys, but satisfactory expression cannot be obtained by such a volume controller.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a keyboard device for eliminating the above'defect in electronic musical instruments.

It is a specific object of the present invention to provide a keyboard device for obtaining a touch-sensitive effect in which increased or decreased volume of sound can be obtained by increasing or decreasing the touch strength of the keys, thereby enhancing the expression obtained by the musical instruments.

The present invention provides a keyboard for an electronic musical instrument including a plurality of keys pivotally supported at their one end, which comprises, in association with each of the keys, a lever located below said key and pivotally mounted at its one end on a pivot shaft in frictional engagement therewith, a weight acting near the free end of said lever, a mechanical-electrical transducer including a movable element attached to the free end of said lever and a fixed element fixed in such position that it applies a varied effect on said movable element depending on the position thereof, said transducer being connected in a sound producing circuit of the electronic musical instrument, whereby if the key is depressed with soft touch strength the free end of the lever is lowered to a position corresponding to the depressed position of said key so that one of said elements of the transducer has relatively small effect on the other element, while if the key is depressed with strong touch strength the free end of the lever is lowered under the action of said weight beyond the position corresponding to the depressed position of the key so that one of the elements of the transducer applies an increased effect on the other element so as to increase the volume of the sound produced.

In accordance with an aspect of the present invention there is provided a keyboard device for an electronic musical instrument including a plurality of keys pivotally supported at their one end, which comprises, in association with each of said keys, a lever located near said key and pivotally mounted at its one end on a pivot shaft in frictional engagement therewith, a weight acting near the free end of said lever, a mechanicalelectrical transducer including a movable element attached to the free end of said lever and a fixed element fixed in such position that it applies varied effect on said movable element depending on the position thereof, said transducer being connected in a sound producing circuit of the electronic musical instrument, a drive member fixed ori the underside of the key to transmit the depression of the key to said lever, a bridle rod fixed on said key to return the lever when the key is released, the above parts being arranged to meet the following conditions:

/y). where a--the distance between the pivot of the key and the position of the bridle rod,

b-the distance between the pivot of the key and the position of the drive member,

x-the distance between the pivot of the lever and the position of the bridle rod,

y-the distance between the pivot of the lever and the position of the drive member.

In accordance with another aspect of the present invention, there is provided a keyboard device for an electronic musical instrument of the above type, in which the weight is directly attached near the free end of said lever.

In accordance with a further aspect of the present invention, there is provided a keyboard device for an electronic musical instrument of the above type, in which the weight is attached to a free end of a leaf spring fixed at its base end and disposed to act near the free end of the lever.

In the device according to the present invention, when the key is depressed with weak touch strength, the key depresses the lever downward through the drive member against the frictional engagement between the lever and the pivot shaft, thus producing sounds with relatively decreased volume. When the key is depressed with strong touch strength, the lever is moved further downward under the action of the weight and the downward displacement of the lever depends on the strength of the touch, so that the distance between the elements of the transducer is rapidly reduced thus increasing the volume of the sound produced. When the key is released, the lever is returned to its original position by the bridle rod, thus ceasing the generation of sound.

Thus the present invention provides a touch sensitive effect, which is maintained while the key is depressed, and consequently the expression of the electronic musical instruments can be substantially improved. In the construction where the weight is .not directly attached to the lever but is mounted on a separate leaf spring, the weight of the lever can be reduced and consequently the friction required at the engagement between the lever and the pivot shaft can be reduced so that irregularities in friction between the levers and the pivot shaft do not cause serious problems in practical use.

BRIEF DESCRIPTION OF THE DRAWINGS The drawings illustrate, by way of example, embodiments of the present invention, in which:

FIG. 1 is a partly broken side view of the keyboard device according to one embodiment of the present invention;

FIG. 2 is a partly broken plan view showing a lever shown in FIG. 1;

FIG. 3 is a partly broken side view showing the operation of the keyboard device shown in FIG. 1;

FIG. 4 is a partly broken side view showing another embodiment of the present invention;

FIG. 5 is a partly broken side view showing the operation of the keyboard device shown in FIG. 4;

FIG. 6 is a partly broken side view showing a further embodiment of the present invention;

FIG. 7 is a diagram illustrating the relationship of the movement of parts shown in FIG. 1;

FIG. 8 is a diagram illustrating relationship of movement of parts shown in FIG. 6;

FIG. 9 is a partly broken side view showing a further embodiment of the present invention;

FIG. 10 is a plan view of a leaf spring shown in FIG. 9;

FIG. 11 is a plan view ofa lever shown in FIG. 9; and

FIG. 12 is a side view showing the operation of the device shown in FIG. 9.

PREFERRED EMBODIMENT OF THE INVENTION The drawings illustrate several embodiments of the present invention. Referring to FIGS. 1-3 showing a first embodiment of the invention, the keyboard device includes apin block I for pivotally supporting the rear end of the keyboard, pins 2 fixed on the upper surface of said pin block, keys 3 each pivotally supported by pin 2, a washer 4 interposed between the keys and the pin block, hook members 5 each projecting from the backward end of the key, springs 6 each connected 3 between the hook member and the pin block to hold the keyin its raised position and a stopper 7 for limiting the downward movement of the keys.

A lever 9 is disposed below each of said keys 3 and pivotally mounted at its one end on a pivot shaft 8 in frictional engagement therewith. In order to provide adjustable frictional engagement between the lever 9 and the pivotshaft 8, the end of the lever is formed with a pair of legs between which the pivot shaft 8 is held and an adjusting screw 10 is arranged to pull the legs together. The friction between the lever and the pivot shaft is so adjusted that the free end of the lever cannot drop downward by the action of its own gravity.

-A drive member 11 covered with a cushioning material 12 is fixed on the underside of the key 3 and is in contact with the lever 9. A weight 13 is attached near the free end of said lever 9, and, in the embodiment shown, the weight 13 is held in a hole formed in the lever 9, shown in FIG. 2. I

- There is a mechanical-electrical transducer, such as a magof a magnet 15. The transducer is connected in a switching circuit of the electronic musical instrument.

In order toreturn the lever 9 to its original position when the key 3 is released, a bridle rod 16 is fixed to the underside of the key 3. The bridle rod 16 passes through a hole 17 in the lever 9 and has a nut 18 which is threadedly engaged on the lower end of said rod and bears against the underside of the lever through a cushioning member 19. When the key is not depressed the bridle rod 16 serves to hold the lever 9 by means of the nut 18 in the raised position shown in FIG. I, and when the key is depressed the bridle lever is lowered to permit the lowering of said lever 9.

The'key 3, the lever 9 and the bridle rod 16 are arranged in such relationship that when the key 3 is depressed the bridle lever 16 islowereda greater distance than that of the lever 9 being lowered by the drive member 11, shown in FIG. 7. In FIG. 7: A-the fulcrum of the key 3,

Bt he fulcrum of the lever 9, namely, the pivot shaft 8, (bthe-position of the bridle rod 16,

Dthe position of the drive member 11, E-the depressed position of the key 3, F-the depressed position of the lever 9, athe distance between the fulcrum A and the position C, bthe distance between the fulcrum A and the position D, x-the distance between the fulcrum B and the position C, y-the distance between the fulcrum B and the position D. The above parts are so arranged as to meet the following condition:

as diagrammatically Under such conditions, when the key 3 is depressed to lower the lever 9, the key 3 and the lever 9 are lowered for the same distance L at the position D, while the bridle rod 16 is lowered more distance than the lever 9 by the distance I at the position C. Thus the lever 9 can make free movement for the distance I at the position C.

In operation, the key 3 is depressed until it comes into contact with the stopper 7. When the key is depressed with soft touch strength, the key 3 is stopped by the stopper 7 and simultaneously the lever 9 is stopped at the position shown by 9 in FIG. 3. In such position the element 14 and the magnet cooperate to produce sound with a relatively small constant volume. When the key is depressed with strong touch strength, the lever 9 continues to descend, after the key 3 has been stopped by the stopper 7, by the action of the weight'I3 for the distance I into the position shown by 9" in FIG. 3. In

this position the element 14 receives strong effect from the magnet 15 to increase the volume of sound, thereby obtaining the above-mentioned touch-sensitive effect. The lever 9 is held in this position while the key is depressed, and when the key is released the lever 9 is raised to the original position so as to cease the generation of sound.

FIG. 4 shows a second embodiment of the present invention, which is substantially identical with the embodiment shown in FIG. 1 except that the lever 9 is so arranged as to move upward. In FIG. 4 the similar parts as thoseshown in the first embodiment are designated by same numerals as used in FIG. I, so that the'construction shown in FIG. 4 will be clearly understood. In FIG. 4, the numeral 20'designates a bearing for supporting the pivot shaft 8.

The operation of the embodiment shown in FIG. 4 is substantially identical with that of the embodiment shownin FIG. 1. As illustrated in FIG. 5, the lever 9 is moved to the position 9' with a weak touch strength, while it is moved to the position 9" with a strong touch strength, thereby obtaining the touchsensitive effect.

FIG. 6 shows a third embodiment of the presentinvention, which is substantially identical with the embodiment of FIG. I except that the lever 9 is arranged in the opposite sense with respectto that of the key 3. In FIG. 6, the similar parts as those shown in FIG. 1 are designated by the same numerals as used in FIG. 1, so that the construction of this embodiment will be clearly understood. In this embodiment, the fulcrum A of a key 3, the fulcrum B of a lever 9, the position C of a bridle rod 16 and the position D of a drive member 11 are so arranged as to meet the relationship as shown in FIG. 8. Under such conditions, when the key 3 is depressed for the distance L, lever 9 is given a freely movable distance I. It will be seen by comparing FIGS. 7 and 8 that the distance l'shown in FIG. 8 is substantially longer than the distance 1 shown in FIG. 7 if the overall length of the key of the former isidentical with that of thelatter. Consequently, the device shown in FIG. 6 can be constructed in substantially smaller size than that shown in FIG. 1 if the same distance I is to be obtained. 1

FIGS. 9I2 show a fourth embodiment of the present invention, which is substantially identical with that shown in FIG. I except that a weight 21 is not fixed in a lever 9 but it is attached to the free end of a separate leaf spring 22 so that the weight acts on the lever near its free end. In these figures, the similar parts as those in FIG. I are designated by the same numerals as used in FIG. I.

In this embodiment, the weight 21 is designed to act on a lever 9, which has a magnetic sensitive element 14 at its free end and is pivotally mounted at its base end on a pivot shaft 8 with frictional engagement therewith. In operation the weight 21 is moved downward more or less, depending on a weak or strong touch strength applied on the key 3, to push the lever 9 downward. While the key 3 is depressed, the lever 9 is held in the position corresponding to maximum displacement of the weight 21 even after said weight is returned by the action of the leaf spring 22, thereby producing sound of the volume corresponding to the position of the lever 9. When the key is released, the lever is returned to its original position by a bridle rod 16 to stop the sound production. When the key is depressed with a soft touch the displacement of the lever 9 is minimal as shown by 9' in FIG. 12, and sound having a predetermined volume is produced. When the key is depressed with a strong touch the lever is moved to the position shown by 9" in FIG. 12, thereby producing sound of increased volume.

It is to be understood that the invention is not limited to the features and embodiments hereinabove specifically set forth, but may be carried out in other ways without departing from the scope as defined in the appended claims.

lclaim:

l. A keyboard device for an electronic musical instrument comprising a plurality of keys swingable about a fulcrum, a lever located near each of said keys, a pivot shaft swingably supporting said lever, a weight disposed near the free end of said lever, a mechanical-electrical transducer including a movable element attached to the free end of said lever and a fixed element disposed in such position that one of said movable and fixed elements applies varied effects on the other of said elements depending on .the relative positions thereof, drive means disposed on said key to transmit the depression of said key tosaid lever, a bridle rod disposed on said key to return said lever when said key is released, and means providing friction force between said lever and said pivot shaft, said friction force being sufficient to hold said lever in a depressed position in accordance with the key depressing strength, said key, lever, pivot shaft, drive means and bridle rod being arranged to meet the following conditions:

(a/b) (x/y) where:

a the distance between the fulcrum of the key and the bridle rod, b the distance between the fulcrum of the key and the drive means,

x the distance between the pivot shaft and the bridle rod,

and,

y the distance between the pivot shaft and the drive means.

2. A keyboard device according to claim 1, in which the weight is directly attached to the free end of the lever.

3. A keyboard device according to claim 1, further comprising a leaf spring having one end fixed and a free end disposed between said drive member and said levcr, said free end being provided with said weight.

4. A keyboard device according to claim 1, wherein said friction force means includes a pair of legs formed at the end of said lever substantially opposite the free end thereof, said legs holding said pivot shaft therebetween, and an adjusting screw means connecting said legs to provide adjustable frictional engagement between said legs and said pivot shaft. 

1. A keyboard device for an electronic musical instrument comprising a plurality of keys swingable about a fulcrum, a lever located near each of said keys, a pivot shaft swingably supporting said lever, a weight disposed near the free end of said lever, a mechanical-electrical transducer including a movable element attached to the free end of said lever and a fixed element disposed in such position that one of said movable and fixed elements applies varied effects on the other of said elements depending on the relative positions thereof, drive means disposed on said key to transmit the depression of said key to said lever, a bridle rod disposed on said key to return said lever when said key is released, and means providing friction force between said lever and said pivot shaft, said friction force being sufficient to hold said lever in a depressed position in accordance with the key depressing strength, said key, lever, pivot shaft, drive means and bridle rod being arranged to meet the following conditions: (a/b)> (x/y) where: a the distance between the fulcrum of the key and the bridle rod, b the distance between the fulcrum of the key and the drive means, x the distance between the pivot shaft and the bridle rod, and, y the distance between the pivot shaft and the drive means.
 2. A keyboard device according to claim 1, in which the weight is directly attached to the free end of the lever.
 3. A keyboard device according to claim 1, further comprising a leaf spring having one end fixed and a free end disposed between said drive member and said lever, said free end being provided with said weight.
 4. A keyboard device according to claim 1, wherein said friction force means includes a pair of legs formed at the end of said lever substantially opposite the free end thereof, said legs holding said pivot shaft therebetween, and an adjusting screw means connecting said legs to provide adjustable frictional engagement between said legs and said pivot shaft. 